Lighting Considerations

When selecting light sources, consider ones with high uniformity to ensure accurate chart readings (refer here for the effects of non-uniform lighting on sharpness measurements). Integrated dimming capabilities can be useful when measuring imaging system quality across different levels of light to simulate multiple real-world scenes.

Uniformity

Uniformity measurements indicate an imaging system’s tendency to become darker the farther away from the center of the image. This occurrence is due to the radial nature of the lens which collects more light in the center and can be particularly strong with wide angle lenses. Testing for uniformity requires light sources with the highest uniformity levels possible. Imatest Lightboxes and Light Panels are available with 90% uniformity or 95% for sizes A through C (an option for the Light Panels), which is sufficient for most devices. If you are testing uniformity for an ultrawide camera, you will need to use a spherical light source because a flat-field light source will not completely fill the FOV in order to test the uniformity of the whole sensor.

Reflective Mounting

Reflectivetest charts can test most image quality factors. High illumination reflective light sources are required for accurate chart measurement. The vertical orientation of our reflective lighting options keeps light levels consistent from the bottom to the top of the test chart. For a more detailed overview of reflective lighting qualities, see our Reflective Lighting page.